Unidirectional blunting apparatus for hypodermic needles

ABSTRACT

An apparatus which is useable to blunt the sharpened distal tip of a hypodermic needle, said apparatus comprising an elongate blunting member which is axially disposable within the lumen of the needle, and which is axially advanceable from a &#34;non-blunting&#34; position within the lumen to a &#34;blunting&#34; position wherein the blunt distal tip of the blunting apparatus protrudes out of the distal end of the needle. A positioning member may be formed on the proximal end of the blunting apparatus, said positioning member being engageable with the needle to alternately hold the blunting member in either its &#34;non-blunting&#34; position or its &#34;blunting&#34; position. One such positioning member comprises a generally cylindrical body having a series of elastomeric engagement fins formed thereon such that, when advanced into the hollow bore of the needle hub, the engagement fins will be proximally deflected and frictionally engaged thereby. Such proximal deflection and frictional engagement of the engagement fins deters proximal extraction of the blunting member, but allows the blunting member to be further advanced in the distal direction.

FIELD OF THE INVENTION

The present invention relates generally to medical devices, and moreparticularly to a blunting apparatus useable to prevent hypodermicneedles from causing inadvertent penetration trauma.

BACKGROUND OF THE INVENTION

In view of the potential for inadvertent infection of healthcare workerswith blood born pathogens such as human immunodeficiency virus (HIV) andhepatitis B. There exists an ongoing motivation to provide safetydevices and apparatus for preventing healthcare workers from incurringinadvertent needle trauma when handling used hypodermic needles.

Examples of devices and apparatus which have heretofore been known forpreventing inadvertent trauma by hypodermic needles (e.g., intravenousneedles) and the like, include those described in U.S. Pat. Nos.5,112,312; 5,120,317 and 5,273,540.

Although many of the heretofore proposed needle safety devices andapparatus do effectively prevent or deter inadvertent needle trauma,none of these prior devices or apparatus are universally usable inconnection with all types of hypodermic needles, in all applicableclinical situations. Accordingly, there remains a need for thedevelopment of additional safety devices and/or apparatus for preventingor deterring inadvertent needle sticks, especially when handling usedhypodermic needles.

SUMMARY OF THE INVENTION

The present invention provides a blunting apparatus which is usable inconjunction with any type of hollow needle having a sharpened distaltip. The blunting apparatus preferably comprises an elongate bluntingmember having a blunt distal tip, and an outer diameter which is onlyslightly smaller than the inner diameter of the needle lumen. Theblunting member is axially disposed within the needle lumen and ismoveable from first "non-blunting" position wherein the blunt distal tipof the blunting member resides within the lumen of the needle, to asecond "blunting" position wherein the blunt distal tip of the bluntingmember protrudes out of the sharpened distal tip of the needle. Apositioning member may be formed on the proximal end of the bluntingmember, such positioning member being engageable with the proximal endof the needle to alternately hold the blunting member in its"non-blunting" or its "blunting" position.

In accordance with the invention, one type of positioning member whichmay be mounted on the proximal end of the blunting member is a generallycylindrical member having a series of annular engagement fins formedthereabout. Such annular engagement fins are preferably formed ofelastomeric or pliable material, and are sized to be advanceable intothe bore of a proximal hub formed on the hollow needle. In this regard,as the engagement fins are advanced into the bore, they will beproximally deflected by and frictionally engaged by the inner surface ofthe needle hub bore. In this manner, such proximal deflection andfrictional engagement of the annular fins with the inner surface of theneedle hub bore will substantially hold the blunting member in eitherits "non-blunting" or its "blunting" position, and will substantiallydeter inadvertent proximal retraction of the blunting member.

Various additional objects and advantages of the present invention willbecome apparent to those skilled in the art upon reading andunderstanding of the following detailed description of a preferredembodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an over-the-needle intravenous cannulaassembly of the present invention having a needle safety sheath mountedthereon.

FIG. 2 is a perspective view of the intravenous cannula assembly of FIG.1 following removal of the needle safety sheath therefrom and followingslight proximal retraction of the needle blunting apparatus which isincorporated therein.

FIG. 3 is an exploded view of the intravenous cannula assembly shown inFIG. 2.

FIG. 4 is a partial longitudinal section view of an intravenous cannulaassembly of the present invention wherein the needle blunting apparatusis in its proximally retracted "non-blunting" position.

FIG. 5 is a partial longitudinal view of an intravenous cannula assemblyof the present invention wherein the needle blunting apparatus is in itsdistally advanced "blunting" position.

FIGS. 6, 7 and 8 are a step-wise illustration of a preferred method ofusing the intravenous cannula assembly of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description and the accompanying drawings areprovided for the purpose of describing and illustrating presentlypreferred embodiments of the invention only, and are not intended tolimit the scope of the invention in any way.

With reference to the drawings, there is shown an over-the-needleintravenous cannula assembly 10 comprising a pliable intravenous cannula12, a needle 14 and a needle blunting apparatus 16.

The intravenous cannula 12 of the assembly 10 comprises an elongatepliable tubular sheath 18 having a distal taper 20 and a hollow lumen 22extending longitudinally therethrough. A Luer hub 24 is formed on theproximal end of the elongate pliable sheath 18, as shown.

The needle 14 of the assembly 10 comprises a rigid, elongate needlemember 26 having a beveled or otherwise sharpened distal tip 28 and ahollow needle lumen 30 extending longitudinally therethrough. Atransparent or partially transparent flash chamber 32 is mounted on theproximal end of the needle member 26. A hollow flash chamber bore 34extends longitudinally through the flash chamber 32 and leads directlyinto the hollow lumen 30 of the needle member 26. A cylindrical distalsleeve portion 38, a tapered distal seating member 36 and an annularshoulder 39 are formed on the distal aspect of the flash chamber 32, asshown.

The needle blunting apparatus 16 of the present invention comprises anelongate rigid blunting member 40 formed of material such as stainlesssteel hypotubing. This rigid blunting member 40 has an outer diameterwhich is slightly smaller than the inner diameter of the needle member26. This elongate rigid blunting member 40 has an opening formed in itsblunt distal tip 42 and a hollow lumen which extends longitudinallytherethrough from the opening in the blunt distal tip to a plurality ofproximal outlet apertures 48 formed in the sidewall of the bluntingmember 40, near its proximal end.

A unidirectional positioning member 44 is mounted on the proximal end ofthe elongate rigid tube 40. Such unidirectional positioning member 44 isa generally cylindrical body having a series of annular, elastomericengagement fins 46 formed thereon. These engagement fins 46 are spacedapart and formed in a longitudinal array, as shown. A proximal endsurface 50 is formed on the proximal end of the positioning member 44.

FIGS. 4 and 5 show the manner in which the blunting apparatus 16 isinserted through the needle 14 of the assembly 10 to prevent theoccurrence of inadvertent skin puncture or other trauma by the beveledor sharpened distal tip 28 of the needle 14. With specific reference toFIG. 4, the blunting apparatus 16 is initially positioned in a first"non-blunting" position wherein only the distal-most ones of theengagement fins 46 are advanced into the proximal portion of the flashchamber bore 34, such that those distal-most ones of the engagement fins46 are in abutment with, and are proximally deflected by, thesurrounding inner wall 45 of the flash chamber bore 34, as shown. Whenso positioned in its first non-blunting position, blunt distal tip 42 ofthe blunting member 40 resides within the lumen 30 of the needle 26, ata spaced distance X₁ proximal to the sharpened distal needle tip 28.

With reference to FIG. 5, when it is desired to advance the bluntingapparatus 16 to its second "blunting" position, distally directed fingerpressure may be applied against the proximal surface 50 of the proximalpositioning member 44, thereby pushing the blunting apparatus 16 furtherthrough the lumen 30 of the needle, to a second position wherein theblunt distal tip 42 of the blunting member 40 extends out of andslightly beyond the sharpened distal needle tip 28, thereby preventingthe sharpened distal needle tip 28 from causing penetration trauma. Whenso advanced to its second "blunting" position, the proximal positioningmember 44 is further advanced into the flash chamber bore 34, causingadditional ones of the engagement fins 46 to be advanced into the bore34 and to come into abutment with, and to be proximally deflected by,the surrounding inner wall 45 of the bore 34. Such frictional engagementand proximal deflection of the engagement fins 46 by the inner wall 45of the bore 34 substantially deters or prevents the blunting apparatus16 from moving or being retracted in the proximal direction. Suchdeterrence against subsequent proximal retraction of the blunting member16 ensures that the blunting member 16 will remain in its second"blunting" position, after the needle member 14 has been removed anddiscarded.

Preferred Mode of Operation

FIGS. 6a-6c show, in step wise fashion, a preferred method of utilizingthe intravenous cannula assembly 10 shown in FIGS. 1-5.

As shown, the protective sheath 11 is initially removed from theintravenous cannula assembly 10, and the blunting apparatus 16 isdeployed in its initial or "first" position as shown in FIG. 4. With theblunting apparatus 16 in such first position, the blunt distal tip 42 ofthe elongate blunting member 40 of the blunting apparatus 16 isretracted within the lumen 30 of the needle member 26 a spaced distanceX₁ from the sharpened distal tip 28 of the needle member 26. This allowsthe sharpened distal tip 28 of the needle member 26 to be introducedpercutaneously into a blood vessel BV. The introduction of the needlemember 26 into the blood vessel BV is verified by the backflow of bloodthrough the lumen 30 of the needle member 26 and the lumen of theblunting member 40 into the flash chamber 32 via the outlet apertures 48within the blunting member 40. After the distal tip of the needle 26 hasbeen inserted into the blood vessel BV, the needle 14 and theaccompanying blunting apparatus 16 (positioned in its "blunting"position) are retracted in the proximal direction, and thumb pressure isapplied to the proximal surface 50 of the positioning member 44 of theblunting apparatus 16, thereby forcing the blunting apparatus 16 to movefrom its first position (FIG. 4) to its second position (FIG. 5)simultaneously with proximal retraction and withdrawal of the needle 14,as shown in FIG. 6b. When in its second position, the distal tip 42 ofthe blunting member 40 is spaced a distance X2 distally beyond thedistal tip 28 of the needle member 26.

Thus, upon its withdrawal, the sharp distal tip 28 of the rigid needlemember 26 is effectively blunted or shielded by the blunt distal tip 42of the elongate blunting member 40 so as to prevent or deter health careworkers, trash carriers or others from suffering inadvertent trauma bythe sharpened distal tip 28 of the rigid needle member 26.

After the needle 14 and blunting apparatus 16 have been discarded, asolution administration tube SAT having a Luer connector LC thereon isattached to the Luer hub 24 of the intravenous cannula 12 to accomplishfluid infusion through the pliable tubular cannula 18 of the intravenouscannula apparatus 12.

It will be appreciated by those skilled in the art that the inventionhas been described hereabove with reference to certain presentlypreferred embodiments only and no effort has been made to exhaustivelydescribe all possible embodiments in which the invention may bepracticed. Indeed, those skilled in the art will recognize that variousaddition, deletions and modifications may be made to the above-describedembodiments without departing from the intended spirit and scope of theinvention. Accordingly, it is intended that all such additions,deletions and modifications be included within the scope of thefollowing claims.

What is claimed is:
 1. A needle assembly comprising:a tubular needlehaving a proximal end, a sharpened distal tip, and a lumen extendinglongitudinally therethrough; a needle hub attached to the proximal endof the needle and defining a longitudinally extending bore which fluidlycommunicates with the lumen of the needle; a blunting member having aproximal end and a blunt distal end, the blunting member being movablerelative to the needle from a non-blunting position whereat the distalend is located within the lumen at a prescribed distance proximal to thedistal tip, to a blunting position whereat the distal end protrudes fromthe distal tip; and a positioning member attached to the blunting memberand comprising:a body attached to the proximal end of the bluntingmember; and a series of pliable engagement fins extending outwardly fromthe body in spaced relation to each other and sized relative to the boreso as to be proximally deflected when distally advanced into the borethereby frictionally engaging the needle hub; the engagement fins beinginitially advancable into the bore to a first position whereat at leastsome of the engagement fins frictionally engage the needle hub tomaintain the blunting member in the non-blunting position, andthereafter further advanceable into the bore to a second positionwhereat additional ones of the engagement fins frictionally engage theneedle hub to maintain the blunting member in the blunting position; thefrictional engagement of the engagement fins to the needle hub beingoperable to deter proximal movement of the blunting member subsequent toits distal advancement to the blunting position thereby minimizing therisk of inadvertant penetration trauma caused by the distal tip of theneedle.
 2. The needle assembly of claim 1 wherein:the bore of the needlehub has a generally circular cross-sectional configuration and is of afirst diameter; the body of the positioning member has a generallycylindrical configuration; and each of the engagement fins extendsradially outward from the body and is of a second diameter which exceedsthe first diameter of the bore.
 3. The needle assembly of claim 1wherein:the blunting member includes a blood inlet opening formed in thedistal end thereof, at least one blood outlet opening formed therein inclose proximity to the proximal end thereof, and a lumen extendinglongitudinally therethrough between the blood inlet and outlet openings;and the needle hub is fabricated from a material which is at leastpartially transparent, and includes a flash chamber which is defined bya distal portion of the bore; the blood outflow opening being disposedwithin the flash chamber when the blunting member is in the non-bluntingposition such that the advancement of the distal tip of the needle intoa blood vessel results in the flow of blood proximally through the lumenof the needle, into the blood inlet opening, through the lumen of theblunting member, and out through the blood outlet opening into the flashchamber.
 4. The needle assembly of claim 3 wherein the blunting memberincludes multiple blood outlet openings formed therein.
 5. The needleassembly of claim 1 wherein the body of the positioning member is formedto include an enlarged proximal end for assisting in the distaladvancement of the engagement fins into the bore.